Settle Plates Research Articles

Transmission potential of Streptococcus pyogenes during a controlled human infection trial of pharyngitis.

Controlled human infection (CHI) models can provide insights into transmission of pathogens such as Streptococcus pyogenes (Strep A). As part of the Controlled Human Infection with Penicillin for Streptococcus pyogenes (CHIPS) trial, we explored the potential for transmission among participants deliberately infected with the Strep A emm75 strain. Three approaches to understanding transmission were employed: the use of agar settle plates to capture possible droplet or airborne spread of Strep A; measurement of distance droplets could spread during conversation; and environmental swabbing of high-touch items to detect Strep A on surfaces. Of the 60 (27%) CHIPS trial participants across five cohorts, 16 were enrolled in this sub-study; availability of study staff was the primary reason for selection. In total, 189 plates and 260 swabs were collected. Strep A was grown on one settle plate from a participant on the second day, using plates placed 30 cm away. This participant received the placebo dose of penicillin and had met the primary endpoint of pharyngitis. Whole-genome sequencing identified this to be the challenge strain. Strep A was not detected on any swabs. In this small sample of CHI participants, we did not find evidence of Strep A transmission by the airborne route or fomites, and just one instance of droplet spread while acutely symptomatic with streptococcal pharyngitis. Although these experiments provide evidence of minimal transmission within controlled clinical settings, greater efforts are required to explore Strep A transmission in naturalistic settings.IMPORTANCEStreptococcus pyogenes remains a significant driver of morbidity and mortality, particularly in under-resourced settings. Understanding the transmission modalities of this pathogen is essential to ensuring the success of prevention methods. This proposed paper presents a nascent attempt to determine the transmission potential of Streptococcus pyogenes nested within a larger controlled human infection model.

Environmental bacterial load during surgical and ultrasound procedures in a Swedish small animal hospital

BackgroundEnvironmental bacteria in animal healthcare facilities may constitute a risk for healthcare-associated infections (HAI). Knowledge of the bacterial microflora composition and factors influencing the environmental bacterial load can support tailored interventions to lower the risk for HAI. The aims of this study were to: (1) quantify and identify environmental bacteria in one operating room (OR) and one ultrasound room (UR) in a small animal hospital, (2) compare the bacterial load to threshold values suggested for use in human healthcare facilities, (3) characterise the genetic relationship between selected bacterial species to assess clonal dissemination, and (4) investigate factors associated with bacterial load during surgery.Settle plates were used for passive air sampling and dip slides for surface sampling. Bacteria were identified by Matrix Assisted Laser Desorption—Time Of Flight. Antimicrobial susceptibility was determined by broth microdilution. Single nucleotide polymorphism-analysis was performed to identify genetically related isolates. Linear regression was performed to analyse associations between observed explanatory factors and bacterial load.ResultsThe bacterial load on settle plates and dip slides were low both in the OR and the UR, most of the samples were below threshold values suggested for use in human healthcare facilities. All settle plates sampled during surgery were below the threshold values suggested for use in human clean surgical procedures.Staphylococcus spp. and Micrococcus spp. were the dominating species. There was no indication of clonal relationship among the sequenced isolates. Bacteria carrying genes conveying resistance to disinfectants were revealed.Air change and compliance with hygiene routines were sufficient in the OR. No other factors possibly associated with the bacterial load were identified.ConclusionsThis study presents a generally low bacterial load in the studied OR and UR, indicating a low risk of transmission of infectious agents from the clinical environment. The results show that it is possible to achieve bacterial loads below threshold values suggested for use in human healthcare facilities in ORs in small animal hospitals and thus posing a reduced risk of HAI. Bacteria carrying genes conveying resistance to disinfectants indicates that resistant bacteria can persist in the clinical environment, with increased risk for HAI.

Auditing the microbiological quality of the air in operating theatres.

The critical relationship between airborne microbiological contamination in an operating theatre and surgical site infection (SSI) is well known. The aim of this annotation is to explain the scientific basis of using settle plates to audit the quality of air, and to provide information about the practicalities of using them for the purposes of clinical audit. The microbiological quality of the air in most guidance is defined by volumetric sampling, but this method is difficult for surgical departments to use on a routine basis. Settle plate sampling, which mimics the mechanism of deposition of airborne microbes onto open wounds and sterile instruments, is a good alternative method of assessing the quality of the air. Current practice is not to sample the air in an operating theatre during surgery, but to rely on testing the engineering systems which deliver the clean air. This is, however, not good practice and microbiological testing should be carried out routinely during operations as part of clinical audit.

Operating Room Airborne Microbial Load: Nonscrubbed Staff Apparel Matters

BackgroundInfection is a leading cause of total joint arthroplasty failure. In previous studies, we found correlations between the level of contamination, concentrations of airborne particles, and the number of staff present. In this study, we focused on the apparel of nonscrubbed operating room (OR) staff to elucidate their contribution to the airborne microbial load. MethodsWe compared hospital-laundered scrubs to disposable coveralls using 2 methods. (1) Participants entered an isolation chamber with a controlled environment and completed tasks for 1 hour wearing both the approved and alternative OR attire. Settle plates collected viable contaminants that were shed by the participants during testing. (2) Lab members conducted standardized maneuvers in a functional OR that simulated typical movements of the nurse, anesthesiologist, implant representative, and entering/exiting staff. An airborne particle counter and settle plates were positioned throughout the OR. After 1 hour, the staff changed apparel and repeated the test. Each session of both phases consisted of 2 tests by the same individuals on the same day. ResultsThere was approximately a 10-fold difference in the settlement rate of viable particles between groups when employing the isolation chamber. The settle rate for scrubs was 5,519 ± 1,381 colony forming units (CFUs)/m2/h, while the settle rate for coveralls was 505 ± 55 CFUs/m2/h (P = .008). During testing in the OR, 218.7 ± 35 CFUs/m2/h were captured for scrubs, compared with 50.5 ± 13 CFUs/m2/h for the coverall (P < .01). The concentration of airborne particles collected for scrubs was 4,952.1 ± 495 particles/m3 and 1,065 ± 53 particles/m3 for the coveralls (P < .01). This was a 77% and 79% reduction for both measures, respectively. ConclusionsThe open nature of standard scrubs allows contaminated particles to escape into the OR environment, whereas the one-piece design of the coveralls restricts pathways of escape. The results of this study may be helpful when developing hospital infection prevention policies.

Group A streptococcal outbreak in a geriatric mental health unit

We report a group A streptococcal outbreak in a geriatric mental health inpatient unit. Communication with cognitively impaired patients, limitations in adherence to hygiene practices, and communal dining may have facilitated transmission. Settle plates aided in identifying a colonized patient. Rapid access to whole-genome sequencing facilitated assessment and management.

Temporal Variation and Phylogeny of Air and Surface Microflora in Relation to Occupancy Patterns in a Higher Education Institution (HEI)

People not only inhale life-sustaining oxygen but also traces of bacteria and even inanimate surfaces introduce microorganisms to one’s bodies. However, the diversity and richness of bacterial communities both indoor and outdoor in a Philippine HEI in relation to human occupancy patterns remain relatively unexplored. Hence, the study aimed to bridge this gap. Microflora were collected using settle plates and swabbing method and identified by comparing their 16s rRNA gene amplicons using the Basic Local Alignment Tool. Several isolates were found to have biological implications in health (e.g. Staphylococcus haemolyticus and Bacillus clarus) and biotechnology (e.g. Rhodococcus pyridinivorans and Bacillus altitudinis). The phylogeny of samples exhibited close cohesion from the genus level, hence forming monophyletic taxa – under the classes Bacilli, Gammaproteobacteria, and Actinomycetes. Furthermore, statistical results established the significant relationship between indoor air and outdoor surface microbial load with the volume of occupants, as opposed to outdoor air and indoor surfaces. The analysis also revealed a strong correlation between the volume of occupants and indoor air microbial concentration (p = 0.002, R = 0.998), likewise in the case of indoor and outdoor surface bacterial contamination (p = 0.036, R = 0.664). Additionally, there was a significant difference in the indoor and outdoor air microbial load following human occupancy patterns in the area (p = 0.018). Findings of the study provide a foundation for understanding air and surface-borne flora, as well as a basis for the enhancement of health and safety standards for building inhabitants.

Bacillus and Aspergillus Prevalence: an Investigation into the Indoor Microbial Quality of Built Environment at the University of Port Harcourt: Nigeria

Background: Inadequate indoor air quality poses significant challenges in school environments, stemming from factors such as overcrowded classrooms, insufficient ventilation, and substandard construction and maintenance practices. Bacterial and fungal contaminants in indoor air present serious health risks. Methods: This institutional-based cross-sectional study focused on selected learning halls to assess bacterial and fungal loads using the settle plate method. Analysis was accomplished through standard cultural methods. Nutrient agar and Potato Dextrose agar plates were exposed for 15 minutes to capture bacteria and fungi, respectively. Results: The study revealed a total bacterial load of 8300 CFU/m3 in the morning and 10400 CFU/m3 in the evening. The highest bacterial load occurred at MBS 25 (3200 CFU/m3 in the morning and 3700 CFU/m3 in the evening), while the lowest was recorded at the Arena (310 CFU/m3 in the morning and 990 CFU/m3 in the evening). Similarly, fungal loads varied, with the Arena recording the highest (620 CFU/m3 in the morning and 690 CFU/m3 in the evening) and the Faculty of Science Auditorium the lowest (310 CFU/m3 in the morning and 620 CFU/m3 in the evening). Bacillus spp. dominated among bacterial genera (25.9%), while Aspergillus spp. was the most prevalent fungal genus (41.7%). Other bacterial genera included Klebsiella, Staphylococcus, Enterococcus, E. coli, and Pseudomonas, while Penicillium and Candida were among the fungal genera. Conclusion: Mitigation strategies should target factors such as temperature, occupancy, and humidity to curb bacterial and fungal proliferation in indoor lecture halls, thus safeguarding the health of students and teachers in the University of Port Harcourt and similar educational institutions.

MICROBIOLOGICAL ASSESSMENT OF INDOOR AIR QUALITY OF STUDENT HOSTELS AND CANTEENS IN A NIGERIAN UNIVERSITY CAMPUS: RISKS ON STUDENTS’ HEALTH

Microbial air contaminants affect the quality of air we breathe and these microbial air contaminants can settle on body parts, clothes, food etc. which poses a serious threat to human health. Therefore, the level of bacterial contamination in various in-door air of the students’ hostels and canteens of Kaduna State University (KASU) and their antibiotics susceptibility patterns was studied. A total of 44 samples were collected from the rooms (18), toilets (18) of the students hostels and canteen (8) of KASU; using the settle plate method. Gram staining and standard biochemical methods were used to identify the bacterial isolates and antibiotic susceptibility testing was determined by disc diffusion method. The bacteria load was between 1.2 x 103 to 6.7 x 103 cfu/ml3. A total of 30 bacteria isolates were identified, Staphylococcus aureus had the highest (9, 30%) occurrence, followed by Streptococcus spp (6, 20%), Bacillus subtilis and Clostridium spp had similar (4, 13.2%) occurrence, The antibiotic susceptibility testing carried out revealed that the Gram negative and Gram positive bacteria isolates were more susceptible to vancomycin (75%, 43.5%), tetracycline (75%, 47.8%) and gentamicin (50%, 43.5%) while high resistance was observed with chloramphenicol (100%, 73.9%), ceftriaxone (100%, 100%), cefoxitin (100%, 73.9%), amoxicillin/clavulanic acid (100%, 87%), and trimethoprim/sulphamethoxazole (100%, 78%). All the indoor samples were contaminated with pathogenic bacteria and there was high level of multidrug resistance. This is very dangerous to the students’ health because it can be a source of transmission infections and antibiotic resistant bacterial strains.

Wearing a Surgical Vest With a Sterile Surgical Helmet System Decreases Contamination of the Surgical Field

BackgroundSterile surgical helmet systems are frequently utilized in total knee arthroplasty procedures to protect the surgeon while maintaining a comfortable working environment. However, common helmet systems pressurize the space between the surgical gown and the surgeon’s skin. In gowns with a back seam, this may allow contaminated skin particles to escape into the surgical field. By measuring bacterial colony-forming units (CFUs), this study sought to determine if occlusion of the open back seam reduced the risk of potential contamination. MethodsFirst, qualitative analysis depicting airflow variations between gown configurations was performed using the Schlieren Spherical Mirror imaging system. Each gown configuration consisted of a sterile surgical helmet and one of 3 gown configurations: a standard gown with rear-tied closure, a standard gown with a surgical vest, and a zippered Toga-style gown. Next, a surgeon then performed simulated surgical activities for 60 minutes within a 1.4 m3 isolation chamber with work surfaces and controllable filtered air exchanges. During each procedure, contaminated particles were collected on sets of agar settle plates positioned directly behind the surgeon. Upon completion, the agar plates were incubated in a biolab, and the number of bacterial and fungal CFUs was counted. The experimental procedure was repeated 12 times for each gown configuration, with sterilization of the chamber between runs. Contamination rates were expressed as CFUs/m2/h. ResultsThe mean contamination rate measured with the standard gown was 331.7 ± 52.0 CFU/m2/h. After the addition of a surgical vest, this rate decreased by 45% to 182.2 ± 30.8 CFU/m2/h (P = .02). Similarly, with the Toga-style gown, contamination rates dropped by 49% to 170.5 ± 41.9 CFU/m2/h (P = .01). ConclusionsWhen used in conjunction with surgical helmet systems, conventional surgical gowns do not prevent potential contamination of the surgical field. We recommend that staff within the surgical field cover the back seam of standard gowns with a vest or don a zippered Toga-style gown.

Effect of Dhupana (medicated fumigation) on the microbial concentration in the indoor air in Kumaragara (pediatric OPD and IPD): an experimental study

Abstract Introduction: Bioaerosols causing infectious diseases are a major concern for the environmental safety in hospital indoors. Chemical fumigation used for controlling infectious bioaerosols leads to several health hazards such as allergic reactions, hyperbilirubinemia, carcinogenicity, and toxicity. Corrosion of metal surfaces, bleaching of fabrics, risk of accidental consumption, high cost, unpleasant odor, flammability, and formation of toxic gases are other concerns. In Ayurveda, Dhupana (medicated fumigation) is advocated for controlling invisible agents capable of disease transmission. It can be a safer alternative to chemical fumigation. However, many ingredients of classical Dhupana preparations are rare or impractical to use; hence, a novel “Shodashanga Dhupa” (16-ingredient fumigation preparation) was formulated using easily accessible ingredients of classical Dhupana formulations. Materials and Methods: The antimicrobial and antifungal activities of Shodashanga Dhupa were ascertained by enumerating colony-forming units (CFUs) in the passive air samples obtained from hospital rooms before and after 1 h of Dhupana. These samples were collected on suitable agar media, and the settle plate method was carried out. Results: There was improvement in the Index of Microbial Air Contamination and a statistically significant reduction in bacterial CFUs in the pediatric outpatient department (P = 0.000218) and in the Panchakarma therapy room (P = 0.000218). There was a statistically significant reduction in fungal CFUs (P = 0.0137) in the pediatric outpatient department and in the Panchakarma therapy room (P = 0.00109) after 1 h of Dhupana. Conclusion: The study suggests that fumigation with common herbs and spices is effective in decreasing bacterial and fungal bioaerosol concentration in the indoor air of hospital rooms, and it can be used as an economical, hassle-free, and safe method of disinfection.

Differences in Aurelia coerulea and Nemopilema nomurai colony proliferation and biofouling invasion at various in situ polyp densities in Jiaozhou Bay, China

Scyphozoan polyp colonies are typically patchily distributed on substrate surfaces at varying densities in the natural environment. We investigated the differences in Aurelia coerulea and Nemopilema nomurai colony proliferation and biofouling invasion at high and low in situ polyp densities in Jiaozhou Bay, China, to explore potential polyp density-dependent effects. The study found that in situ A. coerulea polyp colonies on settling plates consistently survived at high initial density (24.4 ± 2.8 ind•cm−2) over a one-year experiment, but 60% of colonies disappeared at low initial density (0.6 ± 0.1 ind•cm−2). Polyp density in these colonies constantly fluctuated with a significant difference between the two treatments, decreasing by 71.5 ± 37.0% relative to the original level at high initial density by the end of the experiment, but increasing by 237.4 ± 662.7% at low initial density. In contrast, all N. nomurai polyps, whether at high or low initial density (1.9 ± 0.6 ind•cm−2 and 0.2 ± 0.0 ind•cm−2), died after approximately six weeks. Strobilation occurred in A. coerulea, but not in N. nomurai owing to the untimely die-off of polyp colonies. No significant differences in strobilation percentage, number of discs strobila−1 and the calyx diameter of polyps were observed between the two density treatments. Macro-fouling organisms (e.g., ascidians and bryozoans) invaded the settling plates one week after the start of the experiment. Their coverage percentage was significantly lower at high initial polyp density in A. coerulea in a year, but there was no significant difference between both treatments in N. nomurai polyps. Nudibranch predators were discovered in the biofouling communities during the summer, with no significant differences in their numbers between the two treatments for each polyp species. The results indicated that density-dependent effects may play an important role in regulating in situ polyp colony proliferation and combatting biofouling invasion in A. coerulea, but not in N. nomurai. High colony survival and low levels of biofouling invasion at high initial polyp densities in A. coerulea might favor their extensive colonization in natural environment over extended periods of time.

Air quality assessment in (semi) liquid food packaging environments

This study aimed to assess the prevalence of airborne microorganisms within the packaging areas of (semi) liquid food product facilities, considering the impact of outdoor microbiological air, seasonal fluctuations, rural-urban differences and environmental parameters such as temperature and relative humidity. Additionally, the effectiveness of both natural ventilation and air handling units were evaluated against total viable and non-viable particulate matter.Air samples were collected from the packaging areas of fourteen diverse (semi) liquid food producers and the outdoor environment in Flanders, Belgium, over the course of four separate days from January to September 2022. Airborne microorganisms, including total mesophilic plate count (TMPC) and yeast and mould (Y&M) count, were sampled using impaction and settle plate methods on Plate Count Agar and Rose Bengal Chloramphenicol agar, respectively. Simultaneously, a laser particle counter was used to collect and categorise particles into six size-based channels, while environmental parameters were monitored using a hygrometer.The study revealed a wide range of concentrations of airborne microorganisms across various companies (indoor TMPC ranging from 1.35 ± 0.65 log cfu/m3 to 3.42 ± 0.16 log cfu/m3 and Y&M count ranging from 1.22 ± 0.65 log cfu/m3 to 3.10 ± 0.08 log cfu/m3), irrespective of outdoor air quality. Neither relative humidity nor temperature exhibited any influence on TMPC and Y&M count. Companies equipped with high-efficiency filter air handling unit showed decreased concentrations of airborne microorganisms, although this trend did not align with their total particle counts. Moreover, no correlation was observed between total particle count and either TMPC or Y&M count. Additionally, impaction and sedimentation methods demonstrated a strong correlation.In conclusion, the diversity in airborne microorganism concentrations within food packaging areas is influenced by multiple factors, with air handling unit filters playing a pivotal role. High-efficiency filters were found to reduce microorganism levels, but their impact on total particle counts was less pronounced.

An In Vitro Study on the Antimicrobial Effect of Fumigation with Jatu-Sarjarasadi Choorna

In the present scenario, shooting incidence of airborne diseases is a major public health challenge. Therefore, disinfecting our immediate surroundings is quite important. In Ayurveda, Dhoopana is a disinfection method by which drugs of herbal, herbo-mineral or animal origin are used for fumigation. It is a safe, natural and cost-effective method for disinfection. But the effectiveness of Dhoopana has to be proved scientifically for the acceptance of the modern society. Therefore, Jatu-sarjarasadi dhoopa yoga mentioned in Ashtanga samgraha sutrasthana is selected for the study to evaluate its antimicrobial activity. Jatu, Sarjarasa, Ushira, Sarshapa, Patra, Valaka, Vella, Arushkara, Pura, Arjuna are the ten ingredients of the yoga, among which Arushkara is replaced in this study with its Abhava dravya Citraka due to safety reasons. The study was conducted in the procedure room of Prasootitantra Department of Government Ayurveda College Hospital, Tripunithura. The room was fumigated for 30 minutes and kept enclosed for 24 hours. Total microbial colonies were estimated by settle plate method. Petridishes containing culture medium of bacteria and fungi were exposed for 60 minutes in the room before fumigation and 24 hours after fumigation. The sample plates were incubated and total microbial colonies before and after fumigation were counted. The data was statistically analysed using Wilcoxon Signed Rank Test. On statistical analysis, the reduction in total colony count of bacteriae and fungi was found to be significant and showed profound anti-bacterial activity when compared to anti-fungal action. The study concluded that fumigation with Jatu-sarjarasadi choorna has anti-microbial effect.

Spread of Multi-drug Resistant Aerosolised Salmonella sp and Escherichiacoli from Dumpsites in Built Environment of Abraka Town, Nigeria

Waste dumpsites are known to be hot spots for the development of multi-drug resistant (MDR) pathogenic microorganisms, which can be dispersed via aerosols. The dispersal of MDR Salmonella sp and E. coli in dumpsite-infested neighbourhoods of Abraka, a university town, was therefore investigated. Eosine Methylene Blue and Bismuth Sulphite agar plates were used to isolate airborne E. coli and Salmonella sp, respectively using settling plate technique. Air sampling was carried out at 3 neighbourhood dumpsites and at intervals of 50m up to 200m away from the dumpsites along the cardinal directions. The isolates were tested for antibiotics resistance using 10 antibiotics and those with multiple antibiotics resistance (MAR) index≥0.3 were considered MDR and subsequently subjected to plasmid curing, and re-tested for antibiotics resistance. The population of both organisms varied with cardinal directions and dumpsites, but generally declined as the distance from dumpsites increased (E. coli, 2.96-1.72 log cfu/m3 ; Salmonella sp, 2.65-0.00 cfu/m3 ). By overall assessment, mean MAR index for E. coli isolates was 0.39±0.01-0.64±0.04 and 0.37±0.02-0.68±0.03 for Salmonella sp isolates. MDR E. coli and Salmonella sp constituted 26.7-45.7 and 0.0-47.1% of the total population, respectively; and were encountered up to 200m away from the dumpsites at all directions although with decreasing numbers. There were significant reductions (P&lt;0.05) in the MAR indexes of both organisms after curing thereby indicating plasmid involvement in the MDR. In conclusion, the aerosolised plasmid-encoded and chromosome-based genes in MDR organisms from dumpsites can be dispersed in neighbourhoods; and plasmids can spread antibiotics resistant genes by horizontal transfer and compound therapeutic options

Assessment of mould remediation in a healthcare setting following extensive flooding

A new hospital building was close to completion when a large pipe carrying clean water broke, causing extensive flooding. To determine the flood-associated fungal risk to susceptible patients who would use that building. Though standard flood remediation by the builders was relatively straightforward, there was no model for specialist assessment of patient risk due to the flood-associated mould growth. As levels of background airborne fungal spores can be expected to vary significantly over time, we could not use absolute levels to indicate either an excess of airborne fungal spores or successful remediation. Therefore it was decided to use weekly settle plates, exposed at the same time in flooded (test) and equivalent non-flooded (control) areas to compensate for variations in background levels. Flood-related risk was estimated by the ratio between fungal colonies on the test and control sets of settle plates, rather than absolute number. Whereas the physical flood remediation, including the use of 'anti-fungal' treatments, was completed in three weeks post flooding, fungal contamination in flooded areas took 38 weeks to return to control levels and remained so for a further six weeks of observation. By the use of this method, we were able to assure the absence of flood-associated fungal risk to susceptible patients who would use that building. We recommend that infection prevention and control teams consider using this approach should they be faced with similar situations.

Bacteriological Assessment of Indoor Air Quality in Keystone (Male) Hostel, University of Benin, Benin City

This study examined and identified the level of bacteria present in the hostel to evaluate the potential health hazards for the residents and establish guidelines for controlling indoor air quality. Six (6) rooms were sampled out of 25 rooms at the keystone hostel, each with a height of 10 feet, and an average dimension of 9 feet by 10 feet. The study was done in July and November, 2023. Passive air sampling of settle plate method was employed. The isolates were identified using standard cultural and biochemical identification method. The outcome revealed that the concentration of bacteria isolates rose as media exposure time increased. In July, the maximum bacteria concentration was observed in room 37 at 20min (21.5 x 102CFU/m3) and the minimum in room 49 at 20 min (0.02 x 102 CFU/m3. The concentration of bacteria in room 48 at 20 min was (0.1 x 102 CFU/m3), room 47 at 20 min (11.0 x 102 CFU/m3), room 38 at 20 min (16.5 x 102 CFU/m3), room 39 at 20 min (10.5 x 102 CFU/m3), While for the month of November, the highest bacteria concentration was seen in room 37 at 20min (26.5 x 102 CFU/m3) and the least at room 49 at 20 min (0.09 x 102 CFU/m3). The concentration of bacteria at other room 48 at 20 min (0.3 x 102 CFU/m3), room 47 at 20 min (13.5 x 102 CFU/m3), room 38 at 20 min (19.2 x 102 CFU/m3), room 39 at 20 min (15.1 x 102 CFU/m3). A total of seven (7) distinct bacteria species: Escherichia coli (60%), Staphylococcus aureus (100%), Streptococcus pyogenes (50%), Bacillus cerus (30%), Seratia marcescens (30%), Klebsiella spp (50%) and Proteus spp (50%) were isolated and identified in four rooms ( 37, 38, 39, and 47), with six occupants each, while room 48 and 49 had two occupants respectively; hence bacterial load were relatively non-significant. However, Staphylococcus aureus, Streptococcus pyogenes and Bacillus cerus were identified as the most pathogenic isolates seen in the rooms under study. The study highlights the potential impact of occupancy levels on microbial presence within indoor spaces. The results shows that students in rooms 37, 38, 39 and 47 have a high risk of health and disease implications due to poor ventilation and overcrowding, unlike the students in rooms 48 and 49 with low risk of infectious diseases. Therefore, the study recommends a periodic indoor air quality assessment in the students’ hostel, implementation of good health hygiene practices, maintaining environmental sanitation and managing the environmental factors that supports the multiplication of the bacteria especially in the dry season are crucial to preventing the spread of diseases in the hostel.

Investigating Microbial Contamination of Indoor Air, Environmental Surfaces, and Medical Equipment in a Southwestern Ethiopia Hospital.

Healthcare-associated infections, primarily caused by microorganisms, are widespread in healthcare facilities. These infections pose a significant challenge, especially in low and middle-income countries, and have a detrimental impact on patient outcomes. It is crucial to assess the level of microbial load and associated factors to prevent the spread of these infections. The objective of this study was to assess the microbial load and identify the factors associated with it in various wards at Jimma Medical Center. A cross-sectional study conducted at Jimma Medical Center. Indoor air samples were collected using the settle plate method with a 1/1/1 scheme. Inanimate surfaces and medical equipment were sampled using Swabs from a 10 × 10 cm area. A total of 268 samples were collected from 10 rooms. Pertinent information regarding the associated factors was gathered using an observational checklist. A multiple linear regression model was used to identify any associations with the microbial load. Out of the total samples, 181 (67.5%) tested positive for culture, and 270 microbes were isolated. The average load of bacteria and fungi in the indoor air ranged from 124.4 to 1607 and 96 to 814.6 Colony-forming unit (CFU)/m3, respectively. The mean total aerobic colony counts of bacteria and fungi from all surfaces in the wards ranged from 5.25 to 43.3 CFU/cm2. Crowdedness [β = 2.748 (95% Confidence Interval (CI): 1.057-4.44)], the presence of waste material [β = 1.747 (95% CI: 0.213-3.282)], and an unclean room [β = 2.505 (95% CI: 0.990-4.019)] were significantly associated with the microbial load. The microbial load detected in indoor air, inanimate surfaces and medical equipment was posing potential health risks. Consequently, it is recommended to implement regular microbial surveillance of the hospital environment and enhance the infection prevention program to mitigate these concerns.

Bacteriological Assessment of Air Quality in Male and Female Hostels At Federal University Dutsin-Ma, Katsina State

The evaluation of microorganisms present in indoors has become necessary, as how safe the air in our surrounding environment where we spent time is fundamental to our wellbeing. Hence, this study was aimed at assessing the indoor air quality of Male and Female hostel in Federal University Dutsin-Ma, Katsina State. Using the settle plate sampling technique using open Petri dishes containing culture with sampling done twice daily morning and evening consecutively. The microbial isolates were characterized and identified based on macroscopic, microscopic and biochemical characteristics. Total aerobic bacterial isolated ranged between the average of 40cfu/m3 - 164cfu/m3&amp; 20cfu/m3 – 182cfu/m3for male and female respectively. The predominant bacterial species isolated and characterized from all sample were Staphylococcus spp, Micrococcus spp and Bacillus spp. Staphylococcus sp having the highest percentage of 57.7%, followed by Bacillus spp with 32.78% and Micrococcus spp having the least with 9.83%. The result of this studies shows that the organisms isolated which are Staphylococcus spp, Micrococcus spp and Bacillus spp. May be the potential cause of several infections to the students living in the hostels which may be due to overcrowding, limited indoor air and higher activities of the occupants.

Lubrication dynamics of a settling plate

If a flat, horizontal, plate settles onto a flat surface, it is known that the gap $h$ decreases with time $t$ as a power law: $h\sim t^{-1/2}$ . We consider what happens if the plate is not initially horizontal, and/or the centre of mass is not symmetrically positioned: does one edge contact the surface in finite time, or does the plate approach the horizontal without making contact? The dynamics of this system is analysed and shown to be remarkably complex. We find that, depending upon the initial position of the plate and the position of the centre of force, the plate might either make contact in finite time or settle progressively without ever making contact. Our results show an excellent agreement between analytical exact solutions, asymptotic solutions and numerical studies of the lubrication equations.

Assessment of microbial contamination in laser materials processing laboratories used for prototyping of biomedical devices.

Microbial contamination of medical devices during pilot production can be a significant barrier as the laboratory environment is a source of contamination. There is limited information on microbial contaminants in laser laboratories and environments involved in the pilot production of medical devices. This study aimed to determine the bioburden and microbial contaminants present in three laser laboratories - an ISO class 7 clean room, a pilot line facility and a standard laser laboratory. Microbiological air sampling was by passive air sampling using settle plates and the identity of isolates was confirmed by DNA sequencing. Particulate matter was analysed using a portable optical particle counter. Twenty bacterial and 16 fungal genera were isolated, with the genera Staphylococcus and Micrococcus being predominant. Most isolates are associated with skin, mouth, or upper respiratory tract. There was no significant correlation between microbial count and PM2.5 concentration in the three laboratories. There were low levels but diverse microbial population in the laser-processing environments. Pathogenic bacteria such as Acinetobacter baumannii and Candida parapsilosis were isolated in those environments. These results provide data that will be useful for developing a contamination control plan for controlling microbial contamination and facilitating advanced manufacturing of laser-based pilot production of medical devices.